The Primary Mirrors in the 10-M Keck Telescopes Consist of

Multiple Choice

The primary mirrors in the 10-m Keck telescopes consist of

A) a large hollow honeycomb of glass-lightweight but relatively thick to prevent sagging.
B) a large, thin slab of glass whose surface is continuously adjusted by computer-controlled motors.
C) six individual mirrors, mounted so that they all bring the light to the same focus.
D) 36 individual mirrors, mounted so that they all bring the light to the same focus.